[SPv2] Decomposite otherwise-compositable animations that paint nothing.

third_party/WebKit/Source/core/frame/FrameView.cpp

 /*
  * Copyright (C) 1998, 1999 Torben Weis <weis@kde.org>
  *                     1999 Lars Knoll <knoll@kde.org>
  *                     1999 Antti Koivisto <koivisto@kde.org>
  *                     2000 Dirk Mueller <mueller@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Apple Inc. All rights reserved.
  *           (C) 2006 Graham Dennis (graham.dennis@gmail.com)
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
@@ skipping 3063 matching lines @@
       // for slimming paint v2.
       if (targetState >= DocumentLifecycle::PrePaintClean)
         prePaint();
     }
 
     if (targetState == DocumentLifecycle::PaintClean) {
       if (!m_frame->document()->printing() ||
           RuntimeEnabledFeatures::printBrowserEnabled())
         paintTree();
 
-      if (RuntimeEnabledFeatures::slimmingPaintV2Enabled())
-        pushPaintArtifactToCompositor();
+      if (RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
+        Optional<CompositorElementIdSet> compositedElementIds =
+            CompositorElementIdSet();
+        pushPaintArtifactToCompositor(compositedElementIds.value());
+        DocumentAnimations::updateAnimations(layoutView()->document(),
+                                             DocumentLifecycle::PaintClean,
+                                             compositedElementIds);
+      }
 
       DCHECK(!view.hasPendingSelection());
       DCHECK((m_frame->document()->printing() &&
               lifecycle().state() == DocumentLifecycle::PrePaintClean) ||
              lifecycle().state() == DocumentLifecycle::PaintClean);
-
-      if (RuntimeEnabledFeatures::slimmingPaintV2Enabled()) {
-        DocumentAnimations::updateAnimations(layoutView()->document(),
-                                             DocumentLifecycle::PaintClean);
-      }
     }
 
     forAllNonThrottledFrameViews([](FrameView& frameView) {
       frameView.checkDoesNotNeedLayout();
       frameView.m_allowsLayoutInvalidationAfterLayoutClean = true;
     });
   }
 
   updateViewportIntersectionsForSubtree(targetState);
 }
@@ skipping 118 matching lines @@
   if (GraphicsLayer* maskLayer = graphicsLayer->maskLayer())
     paintGraphicsLayerRecursively(maskLayer);
   if (GraphicsLayer* contentsClippingMaskLayer =
           graphicsLayer->contentsClippingMaskLayer())
     paintGraphicsLayerRecursively(contentsClippingMaskLayer);
 
   for (auto& child : graphicsLayer->children())
     paintGraphicsLayerRecursively(child);
 }
 
-void FrameView::pushPaintArtifactToCompositor() {
+void FrameView::pushPaintArtifactToCompositor(
+    CompositorElementIdSet& compositedElementIds) {
   TRACE_EVENT0("blink", "FrameView::pushPaintArtifactToCompositor");
 
   DCHECK(RuntimeEnabledFeatures::slimmingPaintV2Enabled());
 
   Page* page = frame().page();
   if (!page)
     return;
 
   if (!m_paintArtifactCompositor) {
     m_paintArtifactCompositor = PaintArtifactCompositor::create();
     page->chromeClient().attachRootLayer(
         m_paintArtifactCompositor->getWebLayer(), &frame());
   }
 
   SCOPED_BLINK_UMA_HISTOGRAM_TIMER("Blink.Compositing.UpdateTime");
 
   m_paintArtifactCompositor->update(
       m_paintController->paintArtifact(),
       m_paintController->paintChunksRasterInvalidationTrackingMap(),
-      m_isStoringCompositedLayerDebugInfo);
+      m_isStoringCompositedLayerDebugInfo, compositedElementIds);
 }
 
 std::unique_ptr<JSONObject> FrameView::compositedLayersAsJSON(
     LayerTreeFlags flags) {
   return frame()
       .localFrameRoot()
       ->view()
       ->m_paintArtifactCompositor->layersAsJSON(flags);
 }
 
@@ skipping 2002 matching lines @@
 void FrameView::setAnimationHost(
     std::unique_ptr<CompositorAnimationHost> host) {
   m_animationHost = std::move(host);
 }
 
 LayoutUnit FrameView::caretWidth() const {
   return LayoutUnit(getHostWindow()->windowToViewportScalar(1));
 }
 
 }  // namespace blink